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When to Plant Delphinium in Grand Rapids, MN

One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Grand Rapids you can estimate when to plant delphinium by reviewing the USDA zone info.


Planting Calendar for Delphinium

Frost tolerance for delphinium: Tolerant of a very small amount of frost.
When to plant: Up to 3 weeks before last frost.

Since delphinium are one of those plants that can tolerate a tiny bit of cold weather you can plant them a bit earlier in the year than more sensitive plants.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant delphinium
Possibly ok, but a risky time to plant delphinium
Probably not a good time to plant delphinium

The earliest that you can plant delphinium in Grand Rapids is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant delphinium and expect a good harvest is probably August. You probably don't want to wait any later than that or else your delphinium may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your delphinium indoors.

Last Frost Date

The average date of last frost is May 15 in Grand Rapids. In the coldest months of winter you can expect an average low temperature of -35°F.

Always keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Grand Rapids and it can change quite a bit from year to year. Half of the time in Grand Rapids last frost occurs after May 15 so always be ready to cover your delphinium in the event of one of those late frosts.

USDA Zone Info for Grand Rapids

Here is the info for USDA Zone 3b.

Average Date of Last Frost (spring)May 15
Average Date of First Frost (fall)September 15
Lowest Expected Low-35°F
Highest Expected Low-30°F

This means that on a really cold year, the coldest it will get is -35°F. On most years you should be prepared to experience lows near -30°F.

Plants to Grow in Grand Rapids

You may be interested in your other planting guides for Grand Rapids.